It is very easy, so let's start!
Step 1: Empty the Can!
If you don't have any empty cans, get filled ones from the store and drink 'em out! NOW!
O.k. now give them a two day rest, to let the inside of the can dry and then go to the next step.
Step 2: Fill Rice to the Can
Now lay the two cans on a flat surface with their opening facing each other and connect them with duct tape.
Depending on how much rice you use, the sound is different.